Laminar mesh



E March 23, 1965 N.y a. MEARs LAMINAR MESH' Filed July 9, 196s STEP SHEET OF METALLIC MATERIAL WITH DESIRED HOLE PATTERN ill STEP 2 4o myENToR NUR/JAN 5.v MEARS ATTORNEY may impede the view of the instrument.

. This invention is directed toward improvements in the fabrication of a relatively flat web-like structure having a pluralityof accurately defined apertures therethrough and the vproduct formed by this improved fabrication process. t n y The product of this invention finds a variety of uses. For example, it can serve as a holding fixture for use in the assembly of miniature magnetic core arrays, commonly used in high 'speed digital computers, or it may be used for what is commonly referred to as a light deection mask for' viewing oscilloscopes, radar viewing screens and other instruments of a related nature. It is understood that these exemplary uses `are only illustrative and not intended to-be limitive. former caseas a holding fixture for magnetic cores, the

For use in 'the plate-like structure of this invention has an array of closely United States Patentfce spaced cavities arranged in a predetermined pattern, each i one of which must be formed to receive and hold a miniature magnetic core in a standing position. The configuration of the core 'is such that the cavities must be accurately defined inorder toensure that the core remains .in a stable. position during assembly which consists primar'ily'of passing a plurality of wires through the apertures ofthe cores. Additionally, during the step of placing the magnetic cores in the respective cavities in their proper position, vacuum isapplied through an aperture extending-'through the bottom of the holding xture in each of the respective cavities. A more detailed description of this type .of fixture can be found in colpending application of Vacuum Fixture for Magnetic Cores, by .lohn I. Frantzen, Jr., Serial No. 147,513, filed October 25, A1961, and assigned to the same assignee of' `indicating instrument such as an oscilloscope or radar screen. The multitude of apertures or slits in the mask allowthe substantially straight-line light to pass relatively unimpeded therethrough to permit the viewer a clear view of the instrument while the fine lines defining the apertures exclude any angularly directed rays which Both of the devices briey described above must, therefore, have accurately .defined apertures or cavities and in addition thereto must be Astructurally stable when used in their intended fashion. Because of the close spacings of the Iopenings in the devices of this nature in the desired pattern array, it 'has been found that the most feasible methods of making the apertures or cavities or the like have been by photo-etching or electroforming techniques which are well vknown in the art. However, it has been `foundthat a structurally stable member, say foran ex ample, a substantially fiat metallic memberin the order of .D30-050 inch thick, when formedby the etching or electroforming process, does not yield the straight thickness of said member increases;

t l,It is, therefore, .an object of this invention to `provide a structurally stable, generally flat, plate-like member having accurately defined apertures orfcavties formed therein,v

It is a further object of this invention to achieve the foregoing Vobject wherein the structure has a pattern of avmul-titude'v-of closely spaced apertures'.

Still a further object of they inventionl is to provide a device suitable for use as a light deflection mask through which an instrument may be clearly viewed.

These and other more detailedand specificobiects and features will be shown in the course of the following detailed description, reference being had to the-drawings in which: i

FIG. l illustrates an embodiment of this invention fabricated in accordance with vthe novel process taught by this invention; I

FIG. 2 pictorially illustrates the principal steps in the process of this invention;

FIG. 3 illustrates the top view of a portion of another embodiment of this invention fabricated according to the novel process as taught by this invention; I .I

FIG. 4 is a sectional end view of a portionof the embodiment shown in FIG. 3. v-

Referring now to FIG. 1 there is-shown what may be referred to as a light defiection mask for'use' 'as' ascreen over the lface of instruments such as an oscilloscope or radarscope to connethe'lield of vision to a straight line from thel viewers eyes to the-nstrument'ffacei- Inorder to set this invention in its proper perspective, it isfworthwhile to point out that the mesh-like appearance of the detiection mask resulting from the'l circular holes or apertures-passing therethrough in a typical casevi's fformed by fine lines of metallic material, such--asindicated at 10, having a mesh in the order of'lOO lines `per inch. For clarity, only a small portion of the 'mesh-like structure is shown in detail in FIG. l, it beingv understood that the same general pattern exists generally throughout the length and width of the mask. "Furthe`rmore, it should be understoodithat even though eircula'rI apertures are shown in FIG. l other contiguratinsysuch as rectangular slits or combinations of aperture configurations, are contemplated'within the scope o'fv this invention. From this it is obvious that the aperturesA mustihe accurately defined with perfectly straight side walls to insure full viewing capabilities therethrough.` There is also shown in the illustrationof FIG. 1 six indexing lor registration holes indicated at .12 which serve as "guides in properly aligning the multiple layers 'whenstacked together to form the deflectionmask. Additionally, there may be further included holes such as'at"14 which are used for mounting the deflection mask-:to the particular instrument with `which it is to be used"and,-'asffwill be subsequently described in greater detail; for mounting in a holding fixture for assembly.

Referring now to FIG. 2 there is s'hfown"in Step 1 a cross-sectioned end view of one of thev layersfforming the laminar deflection mask. The dim'ensionsvof the apertures orholes,such as indicatedv at 16, 'may' selectively range from one-quarter inch ,"down" totwelve microns and in the typical case of lines.,y inch would be in the order of. .008 inch.` "The thickness of the metallic sheet'may selectively rangelfrom"-01005 up to .010 inch, depending upon the desired hole size and required line definition. ln a typical 4case this thickness would be in the order of .002 inch thick.V Theiregister hole 18 is formed at the Sametime asthepther holes .are formed and provides the means for accurately indexing each of the multiple layers to onev anotlienso that the respectively corresponding apertures.` are in alignment. The individual sheets with the apertures' therethrough Patented Mar. 23, 1965 3 may be formed in any well-known manner which will produce the straight-.sided apertures having the required close spacing relationship in the 'desired pattern. In general, these sheets would be formed either by electroforming or photo-etching processes. It should be pointed out at this juncture that the sheet of metallic -material must be sufficiently thick to insure some stability so that the apertures remain dimensionally fixed with respect to the register hole. On the other hand, the sheet must n'ot be so thick as to result in poorly defined apertures j during the electroforming` or etching process.

`After thevsheets have been fabricated, at least onel surface of ,eachis solder coated. This is'indicated at 20 in Step 2, which shows seven sheets arranged in stacked relationship with a coating layer of solder between each ofthe facing surfaces of the layers. The coating layer of solder which is preferably plated onto the surface of the sheets of metallic material may be in the order of .00005 inch thick.I In order to ensure uniform bonding of the layers to one another, a coating of flux is applied to the solder coating priorto stacking the sheets.

The third step in the processie illustrated in FIG. 2

Vby showing a portionof a holding and alignment fixture in which thesheets are mounted in their stackedA relationship. For clarity the tixture is shown partially disassembled and only two layers of metallic material, 21 and 23, are shown inserted in the fixture with the fixture indexing pin 22, which is affixed to base plate member 24 passing through the respective registration holes in the two sheets. After the plurality of sheets have been stacked on one another with their respective registration holes mating with the corresponding indexing pins, the top plate member 26 is placed over the top layer of the vstack and pressure is applied to the stack by the top plate member via the action of tightening the nut 28 on the threaded portion of bolt 30 which is also atixed to the bottom plate member 24. The entire assembly is then subjected to sutlicient temperature to cause the solder to flow and then is allowed to cool to :room temperature while maintaining the pressure to result in bonding the layers to one another. The top plate member 26 is then removed and the stack, which forms the deflection mask, can then -be removed from the xture. In a typical case fifteen layers of sheets, each of approximately .002 inch thickness, are bonded together to form a deflection mask having a thickness in the order of .030 inch.

The portion of a top view of a magnetic core nest fabricated according to the teachings of this invention is `each of the cavities is a further aperture extending through the fixture, as indicated at 34, through which a vacuum may be applied in order to seat each core in the respective cavities. The cavity may take other forms or shapes, for example as illustrated at 36 in FIG. 4 which shows a funnel-shaped cavity. For the purpose of placing this invention in its proper perspective, in a typical case the core sizes are of .030 inch inside diameter and .050 inch outside diameter and the center-tocenter-'spacing of the cavities is in the order of .080 inch. Reference to the. cross sectioned view of the nesting xture for magnetic cores in FIG. 4 shows its laminated structure in detail.; The apertures 34, through which the vacuum is applied,r are in. the bottom layer and are centrally located ,with respect to the cavity in which the cores 38 are-held. Thenextthree layers, grouped at 40, are'illustrated as havingV apertures of substantially identical dimensions while the top three layers, grouped at 42, have apertures of successively increasing dimensions.

4 The funnel-shaped cavity. 36 formed in .this manner serves to facilitate placing of the cores in the respective cavities. The process for forming the laminar structure is similar to that previously described with relation to the deflection mask. Each of the individual sheets comprising the respective layers of 4the laminar with their respective apertures, registrationh'oles, and mounting holes are individually formed bythe 'well-known photo-etching or electroforming process. `The` solder coating with the covering layer of ilux is then applied to the respective surfaces and the sheets are placed in their desired stacked relationship in the holding `fixture and subjected to the pressure and heat treatment to effect the bonding :between the layers. The resulting product formsja structurally stable nesting fixture having the accurately defined cavities and apertures therein in the desired pattern array.

Although this invention hasvbeen described. in detail with respect to two particular embodiments, it is under stood that no limitation thereto is intended. It is contemplated that other devices having a wide variety of sizes and shapes of apertures in a variety of pattern arrays can be fabricated within the teachings of this invention. Different embodiments of this invention can be made without departing from the spirit and scope thereof, it is to be understood that the invention is not to be limited except as defined by the claims.

What is'claimed is:

l. A fiat rigid laminar mesh formed by a plurality of thin flexible sheets of metallic material each sheet having an identical pattern of holes passing therethrough and a coating of bonding material on at least onemajor surface thereof, the holes in each layer being defined by continuous metallic areas passing between each of the adjacent holes; said sheets bonded together at their respective coated surfaces toform a laminar with the respectively corresponding holes in each sheet centrally located with respect to one another thereby forming an array of accurately aligned apertures each of which provides a line of sight opening passing through the laminar.

2. A at rigid laminar mesh constructed from a plurality of thin flexible sheets of metallic material each having an identical pattern of apertures therethrough the apertures in Veach layer being defined by continuous metallic areas passing between each of adjacent apertures; said sheets arranged in stacked relationship with the respectively corresponding holes in each of the sheets centrally located with respect to one anotherto form a multitude of line of sight openings passing through the stack; and a film of bonding material between the facing major surfaces of said sheets for bonding said sheets to one another in said relationship. i

3. A fiat rigid laminar mesh formed by a plurality of thin iiexible sheets of metallic materialinv stacked relationship, each sheet having an identical pattern of aper tures therethrough the apertures Vot' each layer being delined by continuous metallic areas passing between each of adjacent apertures; said sheetsbonded together with a thin tilrn of solder between each pair of-'facing surfaces with the respectively corresponding holes in the sheets centrally aligned with respect to oneanother to form an array of accurately indexed linefof sight apertures passing through the laminar.

4. The structure described in claim 3 wherein the apertures in some of the sheets are of different dimension nel-shaped openings through the laminar.

wahr-e References Cited by the Examiner UNITED STATES PATENTS Leonard 29-19'1 Kramer 29-191 Crcsswell 29-193 Jones et al. 29-470 Drummond 29--470 DAVID L. RECK, Prmary Examiner. HYLAND BIZOT, Examiner. 

1. A FLAT RIGID LAMINAR MESH FORMED BY A PLURALITY OF THIN FLEXIBLE SHEETS OF METALLIC MATERIAL EACH SHEET HAVING AN IDENTICAL PATTERN OF HOLES PASSING THERETHROUGH AND A COATING OF BONDING MATERIAL ON AT LEAST ONE MAJOR SURFACE THEREOF, THE HOLES IN EACH LAYER BEING DEFINED BY CONTINUOUS METALLIC AREAS PASSING BETWEEN EACH OF THE ADJACENT HOLES; SAID SHEETS BONDED TOGETHER AT THEIR RESPECTIVE COATED SURFACES TO FORM A LAMINAR WITH THE RESPECTIVELY CORRESPONDING HOLES IN EACH SHEET CENTRALLY LOCATED WITH RESPECT TO ONE ANOTHER THERBY FORMING AN ARRY OF ACCURATELY ALIGNED APERTURES EACH OF WHICH PROVIDES A LINE OF SIGHT OPENING PASSING THROUGH THE LAMINAR. 